Generally, the content or the like of minor substances contained in a biological sample such as serum and urine, for example, a protein, is determined by immunoassay, which utilizes an antigen and/or an antibody. The immunoassay utilizes the fact that a binding reaction between an antigen and an antibody corresponding thereto proceeds very specifically and occurs even at low concentrations. Generally, two methods, a sandwich method and a competition method, are known, but an immobilized (solid-phased) antibody or antigen and a labelled antibody or antigen are used in many cases.
Meanwhile, immobilization of these antibodies, that is, immobilization of an antibody to a material or a member having a certain shape is performed routinely in immunoassay, an immune sensor and the like. A latex or polystyrene tube or the like is commonly used as a carrier for immobilizing an antibody. In addition to these, for example, a fibroin film disclosed in Japanese Patent Publication No. H07-122622 and a mesoporous silica porous body disclosed in Japanese Patent Application Laid-Open No. 2004-083501 are exemplified.